class Car:
    """一次模拟汽车的简单尝试。"""

    def __init__(self,make,model,year):
        self.make = make
        self.model = model
        self.year = year
        self.odometer_reading = 0

    def get_descriptive_name(self):
        long_name = f"{self.year} {self.make} {self.model}"
        return long_name.title()

    def read_odometer(self):
        print(f"This car has {self.odometer_reading} miles on it.")

    def update_odometer(self,mileage):
        if mileage >= self.odometer_reading:
            self.odometer_reading = mileage
        else:
            print("You can't roll back an odometer!")

    def increment_odometer(self,miles):
        self.odometer_reading += miles

class ElectricCar(Car):
    """电动汽车的独特之处。"""

    def __init__(self,make,model,year):
        """初始化父类的属性。"""
        super().__init__(make,model,year)

my_tesla = ElectricCar('tesla','model s',2019)
print(my_tesla.get_descriptive_name())